In the handling of yarns and filaments, such as in texturizing processes, it is necessary to guide, direct, and redirect the yarn or filament. Guide means must be provided to support and guide the yarn through the process. Contact between the yarn and each guide results in friction between them, which in turn causes a drag on the traveling yarn. Each guide, and hence contact point, along the path of the yarn increases the tension on the yarn beyond that point. Guides in series have a cumulative effect on the tension induced in the yarn. Because of the limited strength of many yarns and filaments, the number and magnitude of contacts in a process may limit the number of operations and speed of processing which may be used. Moreover, the increased tension in the yarn or filament increases the yarn breakage rate of the process and, in the case of some yarns and filaments such as fine denier nylon, polypropylene, solution-dyed yarns, and especially micro denier yarns, a process may be altogether impractical as a result of an unacceptable breakage rate.
In certain processes, including yarn texturizing processes, it is known to transport the yarn through tubes so as to better control the environment of the yarn and quickly and conveniently thread the yarn through the processing equipment. Where two adjacent tubes are disposed at an angle to one another, it is necessary to provide an elbow connector to join the ends of the tubes. Conventionally, a length of tubing is formed as a curved conduit, the inner surface thereof providing a concave guide surface for the yarn in negotiating the turn. It will be appreciated that such provision results in inordinate friction between the guide surface and the yarn, particularly because the yarn is being urged, at least to some degree, into contact with the surface.
As an alternative to the curved, static surface guide elbow discussed above, guide elbows have been employed which include a bearing roller. In conventional fashion, a rigid length of bent tubing or a housing having a conduit formed therein is provided. Within the tube or housing is disposed a freely rotatable roller having a groove formed therein for receiving the yarn. The roller is disposed at the apex of the turn, the axis of its rotation being perpendicular to the plane defined by the turn.
While providing certain benefits such as reduced drag on the yarn, guide elbows equipped with rollers as described above have certain drawbacks. Because the elbows are fixed in position, for a given juncture it is necessary to use an elbow preformed to a certain angle or modify the system to accommodate the angle dictated by the elbow. Guide elbows of the prior art have been formed of transparent material, however, the entire housing is formed from the material providing a weaker housing than may be desired. Even if the roller is visible from exteriorly of the elbow, the guide elbows of the prior art do not provide a means for easily determining whether the roller is spinning freely. Moreover, the guide elbows of the prior art do not provide a convenient means for replacing the guide elbow.
Thus, there exists a need for a guide elbow having a bearing roller which may be selectively adjusted for use in joining adjacent tubes disposed at a range of angles with respect to one another. There exists a need for such an adjustable guide elbow which may be secured at a given angle and re-adjusted when desired. Moreover, there exists a need for such an adjustable guide elbow which provides an easy and convenient means for detecting whether the roller is spinning properly. There exists a need for such a guide elbow which provides for convenient removal and replacement of the roller.